Mine roof supports



Feb. 6, 1968 G, J. BEST ETAL 3,367,118

MINE ROOF SUPPORTS Filed Nov. 29, 1965 5 SheetsSheet 1 INVENTORS GEORGE J. BEST J'OSEPH GASKELL. BY

Feb. 6, 1968 G. J. BEST ETAL 3,367,113

MINE ROOF SUPPORTS INVENTORS GEORGE J. BEST JOSEPH GASKELL Feb. 6, 1968 l G, J. BEST ETAL 3,367,118

MINE ROOF SUPPORTS Filed Nov. 29, 1965 3 Sheets-Sheet 5 INVENTORS GEORGE J. BEST JOSEPH GASKELLBY United States Patent 3,367,118 MINE ROOF SUPPORTS George J. Best and Joseph Gaskell, Wigan, Lancashire,

England, assignors to Gullick Limited, Wigan, England,

a British company Filed Nov. 29, 1965, Ser. No. 510,342 Claims priority, application Great Britain, Jan. 6, 1965, 508/ 65 3 Claims. (Cl. 61-45) ABSTRACT OF THE DISCLOSURE In a self-advancing mine roof support having a pressurefiuid ram for pushing over a conveyor and advancing the support, the piston rod of said ram is provided with an extension bar for connecting it to the face conveyor. The extension bar has a socket at one end in which the outer end of the piston rod is loosely anchored or alternatively the outer end of the piston rod has a socket in which an end of the extension bar is loosely anchored. The socket is formed with a conical passageway into which the end of the piston rod or the extension bar, as the case may be, passes with a predetermined amount of clearance. The walls of this conical passageway limit the amount by which the piston rod and extension bar can move angularly out of alignment.

This invention is for improvements in or relating to mine roof supports for use in longwall mining.

The invention is concerned with powered or self-advancing mine roof supports of the kind incorporating pressure-fluid ram means whereby the conveyor which extends along the coal face and receives and carries away the coal as it is cut from the face by the cutting machine or plough, is pushed towards the coal face progressively as cutting of the coal proceeds, after which, using the conveyor as an anchorage, the ram means is operated so as to advance the support up to the conveyor. One example of a support of this character is described and claimed in the specification of our U.S.A. Patent No. 3,197,966.

With longwall mining it is necessary to provide a travelling track or passageway through, or in front of, and along the series of supports for the men working at the coal or other mineral face.

It is most desirable and in fact essential in low seam workings that this travelling track or passageway should be as unobstructed as possible. Heretofore, a major restriction or obstruction has been the pressure-fluid ram which, as above described, is incorporated in each support for pushing over the conveyor and then advancing the support.

This has to some extent been overcome by connecting the ram to the conveyor by a piston extension member or relay bar which can be relatively flat or low-set and does not, therefore, materially obstruct or interfere with movement along the travelling track.

An object of the present invention is to provide improvements in or modifications of this relay bar arrangement and in particular to avoid possible buckling or other damage to the piston rod of the ram.

According to the present invention there is provided a self-advancing mine roof support having a pressure-fluid rarn for pushing over a conveyor and advancing the support, the piston rod of said ram being provided with an extension or relay bar for connecting it to the conveyor, wherein the piston rod is connected to the relay bar by means which permit relative angular movement, out of alignment, between the piston rod and the relay bar and Patented Feb. 6, 1968 ice wherein means is provided at said connection for limiting said angular movement. Thus arrangement avoids the off-centre load, which has to be taken by the piston rod, ever reaching such a magnitude that buckling of the piston rod will result.

In one preferred arrangement the relay bar has a socket or the like at one end in which the outer end of the piston rod is loosely pivoted or anchored. The socket is formed with a conical or like passageway or hole through which the end of the piston rod passes, with a predetermined amount of clearance, the walls of said conical passageway or hole limiting the amount by which the piston rod and relay bar can pivot out of axial alignment.

One particular embodiment of the invention will now be described, by way of example, as applied to a roof support similar to that described and claimed in our U.S.A. Patent specification No. 3,197,966. In the following description reference will be made to the accompanying drawings in which:

FIGURE 1 is a side elevation of the support partly in section,

FIGURE 2 shows the relay bar and piston rod arrangement in the relative positions they occupy when in alignment, and

FIGURE 3 shows the relay bar and piston rod arrangement in the relative positions they occupy when there is maximum misalignment.

Briefly, the support shown in FIGURE 1 comprises a rear unit 10 and a front unit 11.

The rear unit 10 has a base 12 on which are mounted in rectangular formation four hydraulically extensible telescopic props or legs 13. These props or legs support at their upper parts, in the usual way, a roof-bar structure or canopy 14.

Housed in the rear unit 10 is a hydraulic ram for pushing over the conveyor and advancing the support. This hydraulic ram comprises a cylinder 15, which is conveniently pivotally supported in the rear unit by laterally extending trunnions or the like 15a, and a piston rod 16.

The front unit 11 comprises a base 17 and a single hydraulically extensible telescopic prop or leg 18 which supports at its upper part, in the usual way, a cantilever roof-bar structure 19 hingedly or pivotally connected to the roof-bar structure 14 at 20.

The rear unit and the front unit are articulated or pivotally linked together at their lower parts by a linking or articulating arrangement not shown. This linking or articulating arrangement can be as described in our aforementioned specification No. 3,197,966, or otherwise.

The piston rod 16 is connected to a spill-plate or bracket 21 on the conveyor C by means of a clevis 22 and a relay bar 23. It will be noted that the relay bar does not materially obstruct the travelling track T.

The connection between the outer end of the relay bar 23 and the clevis 22 is in the form of a pin and vertical slot arrangement 24, 25 which provides for some freedom of movement in the vertical direction.

At its other end the relay bar is provided (see more particularly FIGURES 2 and 3) with a socket member 26 in which the piston rod 16 is hingedly connected by means of a pin 27, the ends of which are located in oversize holes 28 in the Wall of the socket with a material amount of clearance. The pin 27 is driven into or otherwise secured in a hole in the end of the piston via one of the holes 28 in the wall of the socket.

The end of the piston rod remote from the clevis 25 passes into the socket member 26 through a conical hole or passageway 29.

It will be noted from FIGURE 3 that the maximum angular misalig-ment between the piston rod and the relay bar is limited by the conical seating or wall'of the conical hole or passageway 29 and the pin or bolt 27. By varying the taper of this conical seating, to suit the length of the piston rod, the off-centre loading effect may be varied.

The arrangement above described may be modified by providing the socket 26 on the outer end of the piston rod instead of on the relay bar.

We claim:

1. A self advancing mine roof support having a pressure-fluid ram for pushing over a conveyor and advancing the support, said ram including a piston rod member and an extension bar member connecting said support to the conveyor, one of said members having a socket at one end in which the adoining end of the other said member is loosely anchored, said socket being formed with a conical passageway into which the end of the other said member passes with a predetermined amount of clearance, the walls of said conical passageway limiting the amount by which said members can move angularly out of alignment.

2. A mine roof support as claimed in claim 1 wherein the other said member is hingedly connected to said socket by a pin, the ends of which are located in over-size holes in the wall of the socket.

3. A mine roof support as claimed in claim 2 wherein said socket is on said extension bar member, the other end of which is connected to said conveyor.

References Cited UNITED STATES PATENTS 3,258,108 6/1966 Cowlishaw 6145 JACOB SHAPIRO, Primary Examiner. 

